Main dataset interest
My general question is, how chemical properties define the quality of the red wine?
There are interesting features in this dataset, each of them describing an important property of the red wine. Density, pH, sulphur dioxide, and sulphates are, in my opinion, the most important ones, in order to measure the quality. Let’s see what can we find looking at those variables.
pH
This variable indicates the acidity level of the wine. The scale goes from 0 (very acid) to 14 (very basic). But most of red wines are between 3 and 4.
It’s quite surprising that levels of pH are lower on low-quality and high-quality wines.
Density of water
The level of this variable depends on alcohol percentage and sugar.
Density levels are also lower on low-quality and high-quality wines.
Free Sulphure Dioxide
The free form of SO2 exists in equilibrium between molecular SO2 (as a dissolved gas) and bisulfite ion. It prevents microbial growth and the oxidation of the wine.
Again, the levels for this variable are lower for low-quality and high-quality wines.
Sulphates
Additive contributing with sulphure dioxide gas (S02) levels, acting as an antimicrobial and antioxidant.
Sulphates levels are lower for low-quality and high-quality wines as well.